Brandon Rene Guerra, 29, was arrested early Saturday during a traffic stop in the 2400 block of Hemlock Street.
Police said Guerra's 24-year-old ex-girlfriend called them to a home in north Oxnard on Thursday and told them Guerra forced his way into her car and made her drive around the city against her will. The woman's 4-year-old son was in the car at the time, and Guerra also brandished a handgun in the incident, the woman told police.
Guerra was taken into custody without incident. A replica handgun was located in the vehicle, police said.
Guerra was arrested for kidnapping, child endangerment, violating a domestic violence restraining order, possession of a firearm by an ex-felon and brandishing a firearm, police said.
Anyone with information is asked to call the Oxnard Police Department at (805) 385-7740.